How to rectify uneven Merbau deck?

[EricMiller94]

My guge merbau deck is generally holding up well.  I’ve just cleaned it w Cabots deck cleaner and am ready to apply annual oil.  Before I do…you can see the deck has patches of different colours.  What can I do to even thie colour on the deck as I apply the oil?

90% is same colourThis patch is different. Near the back door so it’s really evident.Close up shot

[MitchellMc]

Welcome to the Bunnings Workshop community @EricMiller94. It's terrific to have you join us, and many thanks for your question about preparing a Merbau deck.

Could you please tell us a little more about what products were previously used to coat the deck? It doesn't appear that it was just oil and stain.

Currently, I can not see any other option than to sand the deck to remove whatever previous coating has been applied. I'm keen to hear more about what that coating might have been.

Please let me know if you have any questions.

Mitchell
 

[EricMiller94]

Hi Mitchell,

No other products have been used other than decking oil.  The only other factor is the awning covering the deck has a leak which bleeds through the upstairs balcony and occasionally drips onto the deck.  The “white” areas of discolouration are probably the result of these mineral-rich drippings.  I power washed these deposits off but there’s still the discolouration.

[EricL]

Hi @EricMiller94 

I'm afraid these mineral-rich drippings have bleached and eaten away the former oil cover on the surface. Those white blemishes represent the mineral deposits that have spread due to the continuous dripping. The light sections where you can see the actual timber surface are part of the areas that the drippings have worn away. Oiling over them now is a guarantee that the finish will be uneven and patchy at best.

I can only suggest what my teammate has already recommended, and that is to sand the surface back to timber and re-oil the decking panels. Sanding the surface back will remove all the blemishes and mineral deposits that might have attached itself onto the decking surface. I'm afraid there is no easy quick patch that can be applied that will not make it stand out. 

Here is a link to ideas and inspiration: 

Here are some handy step-by-step guides:

• How to sand a deck
   
• How to stain a deck
   
• How to maintain a deck

Please remember to wear personal protection such as gloves, goggles and a paint rated mask.

If you have any other questions we can help with, please let us know. 

Eric